A. 4 Months
Feedback We can simply compute per month investment of both partnership
Raj invested Rs 76,000 for 12 months and Monty invested Rs 57,000 for x months.
Now 76000 × 12 / 57000 × x = 2 :1
=> 76 × 12 / 2 = 57x
=> x = 8
So Monty invested his money for 8 months and he joined after 4 months.